Cationization of cellulosic membranes by polyamine grafting, Michael reaction and Hofmann degradation was studied. Blood compatibility and inorganic phosphate permiability of these membranes were also studied.Polyallylamine(PAAn) and hexamethylene diisocyanate(HMDI) were used as the polyamine and the crosslinking agent for the cationization by polyamine grafting. About 0.02 mu mol/cm^2 of HMDI was combined within one hour reaction in toluene at 30ﾟC.The reaction of PAAn and urethanated membrane readily took place at room temperature. Degree of cationization was enhanced by using DMSO as a solvent instead of toluene. Cationic membranes of various zeta-potentials could be prepared by changing the reaction condition and the molecular weight of PAAn.Michael reaction using dimethylaminopropylacrylamide(DMAPAA) and its quaternary amine compound(TMAPAA) proceeded favorably, and 0.34 mu mol/cm^2 of DMAPAA and 0.8 mu mol/cm^2 of TMAPAA were combined at 45ﾟC.Improvement of the inorganic phosphate dialyzance was observed in these membranes.Hofmann degradation of carbamoylethylated cellulose membrane readily proceeded and aminoethylated membrane of 0.094 mu mol/cm^2 was obtained. Ethylenediamine(EDA) or polyallylamine(PAAn) was attempted to react with N-chlorinated membrane to prepare cationic membranes under a mild alkaline condition. The amino group content was 0.054 mu mol/cm^2 and 0.229 mu mol/cm^2 for EDA combined membrane and PAAn combined membrane, respectively. Almost all cationic membranes obtained in this study showed the suppression effect of complement activation from the CH50 measurement.4.再生セルロース膜のカチオン化にホフマン反応が利用可能であり、置換度0.02以下であれば膜強度の低下を5%以内に抑えることが可能であった。5.N-Cl化膜とエチレンジアミン(EDA)あるいはポリアリルアミン(PAAn)との反応により、温和な条件で陽荷電膜が調製できた。6.ホフマン反応による陽荷電膜も補体活性抑制効果を有していた。従って、この性質は1級〜4級を問わず、アミノ基に共通した特性であると推察される。